Electric cord set



Jam F. c. DOUGHMAN 2,186,578

ELECTRIC CORD SET Filed Dec. 2, 1937 2 Sheets-Sheet l INVENTOR.

WATTORN .V

Jan. 9, 1940. c. DQUGHMAN 2,186,578

ELECTRIC CORD SET Filed Dec. 2, '19s? 2 Sheets-Sheet 2 Patented Jan. 9,1940 1 UNITED STATES PATENT OFFICE ELECTRIC CORD SET Fer-man O.Doughman, Stamford, Conn., assignor to Electrolux Corporation, Dover,Del., a corporation of Delaware Application December 2, 1937, Serial No.177,740

3 Claims.

My invention relates to an electric cord set and more particularly. toan electric cord set with means incorporated in it for filtering orby-passing high frequency electric currents.

In the operation of electrical appliances high frequency electriccurrents may be generated or pulsations produced which do not affect theproper functioning of the appliance. However, these high frequencycurrents or pulsations, if transmitted through the supply lines,antenna, or ground connectors to a radio circuit, may produce static inthe radio circuit and so interfere with the reception of one or moreradio programs. While the operation of appliances does not often affectradio reception when radio interference does occur it may be eliminatedby connecting a so-called radio filter to the appliance. The radiofilter usually consists of condensers connected to the appliance forfiltering out or by-passing the high frequency currents or pulsations.In view of the fact that it is seldom that the operation of an appliancewill affect radio reception it is not desirable to build a radio filteror interference eliminator into appliances. A radio interierenceeliminator which can be conveniently connected to an appliance causingradio interference is highly desirable.

In accordance with my invention, a cord set is provided with a radiofilter or interference eliminator incorporated in it which may be usedwith any appliance that tends to produce radio interference, or may beused with all appliances without the necessity of determining which oneof them does produce the interference. By in- O corporating a radiofilter in the cord set and covering it with a flexible material it ismade rugged so that it will withstand the hard usage to which portableappliances are subjected.

What I consider to be novel and my invention may bebetter understood byreference to the following specification and appended claims whenconsidered in connection with the accompanying drawings, in which Fig. 1is a view showing a radio filter incorporated in an auxiliary cord setconnected between a vacuum cleaner and a conventional cord set;

Fig. 2 is a sectional view of the auxiliary cord set of Fig. 1;

Fig. 3 is an end View of the auxiliary cord set of Fig. 2;

Fig. 4 is a plan view of the auxiliary cord set of Fig. 2;

Fig. 5 is a sectional View along line 55 of .n Y v I Fig. Gis asectional view taken along the line 66 of Fig. 2;

Fig. '7 is a schematic wiring diagram of the filter;

Fig. 8 is a modified form of cord set;

Fig. 9 is a sectional View along line 99 of Fig. 8; i

, Fig. 10 is a sectional view along line ill-40 of Fig. 8;

Fig. 11 is an end view looking in the direction of arrows HIl of Fig. 8;and

Fig. 12 shows another modified form of cord set.

Referring to the drawings, numeral I0 designates an auxiliary cord setconnected between a: vacuum cleaner H and a conventional cord set i2.Vacuum cleaner II is shown by way of an example of a portable appliancewith which the invention may be used. Vacuum cleaner II is of the typehaving a. cleaner unit l3 supported on the floor and moved from place toplace by pulling on a flexible conduit or hose M to which is connected acleaning tool 15. The unit [3 is usually connected to a source ofelectrical supply by means of a cord set [2. If radio interferenceshouldbe encountered. in the operation of the appliance it may beeliminated by connecting the auxiliary cord set I0 between the applianceand the usual cord set.

Auxiliary cord set Ill has incorporated in it a radio filter unit IS. Aschematic diagram of the filter unit I6 is shown in Fig. 7. Twocondensers I! and I8 are connected together at I9- Instead of twocondensers a single condenser may be used with a tap intermediate itsends. The condenser I7 is connected to two conductors and 21 which areadapted. to be connected at one end to an appliance and at the other endto a source of electrical supply. The condenser I8 is connected by meansof its terminal that is com-- men with a terminal of condenser I! toconductor 2i. The other terminalof condenser I8 is connected to a groundconnection at 22. Instead of this ground connection a connection may bemade to the frame or casing of the appliance. The condensers l1 and I8by-pass or suppress the high frequency currents or pulsations so thatthey are not transmitted over the electrical supply system.

Referring particularly to Figs. 2 to 6, the filte unit 16 isincorporated in the auxiliary cord set l0 adjacent a male plug 23. Twoleads 24 and 25 are brought out at one'end of the filter unit l6 one ofthe leads being connected to a common terminal of two condensers or toan intermediate tap of a single condenser. Athird lead 26 is brought outat the other end of filter unit I6.

While filter unit I6 is shown as of a slender and relatively longcylindrical shape, other shapes or forms of filter unit may be used.Leads 24 and 25 are connected to two terminals 2'! of plug 23 to whichconductors 23 and 29 are also connected. Lead 26 is connected to a thirdconductor 39. Conductors 22 and 29 are connected at their opposite endsto two terminals 3| of a female connector 32. Conductor 39 is connectedat its opposite end to a contact 33. Two spacers 34 of disc shape arepositioned on filter unit I6 adjacent opposite ends. The spacers 34 arepreferably formed of a substantially rigid material such as hard rubber;Two recesses are provided in the spacers 34 through which the conductors28 and 29 may pass. It may-be found desirable to use more than twospacers .34 de- "alug 4| preventing the connector 32 from fitpendingupon the size of the filter unit I6. The spacers 34 perform the-dualfunctions of protecting the filter unit I 6 from unusual crushing forcesand the conductors 28 and 29 from strain tending to sever theirconnections to the. ter- Ininals 21 byttwisting.

An overall covering 36 of flexible insulating material preferably softrubber is provided for the auxiliary cord set It]. Covering 36 can bestbe formed in steps by first forming it on the conductors 28, 29, and 30and then separately on the filter unit I3 and terminals 27 forming plug:23 .and the terminals 3i forming connector 32. If a rubber compound isused for covering 36 itmay be vulcanized or cured in successive .stepsas it is. applied' Plug 23' is provided with a-lip 3.1 integral withcovering 36 and extending to. substantially the ends of terminals 2?.Lip 3:7! provides a protective insulating covering for the terminals 27to prevent a shock or short circuit upon the connection ofa connector 38of cord set I2 after a plug-.39 has already been connected .to a sourceof electrical supply. Lip 31 also serves to provide a moisture andwaterproof protection for the terminals .21 .when connector 38 isconnected to them.

.Contact 33.is carried by connector 32 and extends .exteriorly of thecovering 36 at one side of the body of connector 32. When connector 32is connected to an appliance such as vacuum cleaner II the contact 33engages a metallic portion of the casing of cleaner unit I3 as at 40. Toprevent the reversal in position of the connector 32 so that a goodconnection between thecasing .of cleaner unit I3 and contact 33 isassured the body of connector .32 is formed with ting butin oneposition.

.In the use of vacuum cleaners of the type of vacuum cleaner II at timesthecleaner unit I3 may, standupright on .its .rear end shown at theright in Fig. 1. Any protuberance extending from the connector 32 mayinterfere with the placing of the cleaner unit I3 in this position ormay be damaged. To prevent such a possibility. the filterunit I6 'ismounted adjacent theplug 23 and sufficient length of conductors 28,29,and 36 provided between the connector 32 and filter unit I6.to permitthebending of the cord set In adjacent the connector 32 withoutanydanger of damage to the filter unit Hi.

In a modified form of construction shown in Figs. 8 to .;11 filter unitI6 is incorporated in a cordset 42 of sufficient length so that it maybe substituted for the conventional .cord set I2 instead of being usedin conjunction with. itas in nector 59.

the case of the auxiliary cord set I 0 described above. Similar partsare designated by the same numerals used heretofore. The two leads 24and connection to a grounded circuit at the recepta'cle or convenienceoutlet (not shown) to which the plug 45 is connected. 7

The conductors 28 and 29 are connected at their opposite ends to twofemale terminals 48 and 49, respectively, of a three'contact con- Thethird terminal 5i of connector 59 located between the terminals 48 and49 is connected to conductor 39. Terminal 5| is adapted to-complete aconnection to the metal frame of the casing of cleaner unit I3 at apoint not shown in the drawings. By this arrangement with the terminal5I for connecting the conductor 58 it does not matter whether theterminal 48 or 49 is positioned at the top so the connector 58 may beconnected in either position.

vThe conductor 36 in addition to connecting the casing of cleaner unitI3 to vthe lead 26 of filter unit I6 also connects the casing to groundthrough wire 46 and prong 41. In some localities the connection of thecasing of a portable appliance to ground is considered desirable and inthe case of washing machines and similar appliances is required. Byusing cord set 42 it would be unnecessary to make any other or specialconnection between the appliancecasing and ground. Two discs 52 ofvulcanized fiber or like material are located on the filter unit I6 atopposite ends. Recesses 53 permit the passage of conductors '28, 29, and36 through the discs 52 and serve to position the conductors around thefilter unit I6. To permit a bond between the discs 52 and an overallcovering 54 of flexible insulating material a plurality of spaced holes55 are provided in discs 52 through which the material of covering 54may extend. It may be found desirable in some cases to omit from thecord set 42 the conductor 39 and terminal 5| or the wire 43 and prong41. However, one or the other of the connections forlead 26 of filterunit I6 should be provided. In the manufacture of cord set 42 the samesteps can be followed as in the case of auxiliary cord set I8.

In the modification illustratedin Fig. 12 the filter unit I6 is combinedwith a three terminal connector 56. This construction may be used wherea protuberance from the connector is of no concern. The leads 24 and 25are connected to the conductors 28 and 29, respectively, intermediatetheir ends. The adjacent ends of conductors 28 and 29 are connected tothe two outside terminals 51 and 58, respectively, of

connector 56. Lead 26 is connected directly to stituted for theconnector 56.

What I claim is:

1. In an electric cord set, a connector having a plurality of electricterminals, a condenser relatively long in comparison to its Widthconnected to said terminals and located in juxtaposition to saidconnector, a plurality of substantially rigid spacers surrounding andspaced apart longitudinally along said condenser, and a unitary coveringof: flexible insulating material surrounding said connector and saidcondenser, said rigid spacers acting to protect said condenser frominjury by the operator of an appliance with which the said cord set maybe associated.

2. In an electric cord set, a connector having a plurality of electricterminals, a plurality of condensers extending longitudinally from saidconnector, a plurality of substantially rigid discs extending around andspaced apart longitudinally along said condensers, and a unitarycovering of flexible insulating material surrounding said connector andsaid condensers, said rigid disks acting to protect said condenser frominjury by the operator of an appliance With which the said cord set maybe associated.

3. In an electric cord set, a plurality of electric terminals, anelectric condenser relatively slender in comparison with its lengthconnected to said terminals and positioned longitudinally in line withsaid terminals, a plurality of vulcanized fiber spacers surrounding andspaced apart longitudinally along said condenser, and a unitary coveringof flexible insulating material for said terminals and said condenser,said fiber spacers acting to protect said condensers from injury by theoperator of an appliance with which the said cord set may be associated.

FERMAN C. DOUGHMAN.

